Interpretive Summary: Coryza is a highly contagious respiratory disease of turkeys caused by Bordetella avium. Poults with coryza may be observed sneezing, having a discharge from the eyes and/or beak, having difficulty breathing, and exhibiting a reduction in weight gain. Onset of these clinical signs generally occurs at 2 to 6 weeks of age, and morbidity may reach 80 to 100%, with death typically less than 10%. To date, there have been no studies that have examined whether the genetic background of poults has an influence on their susceptibility to coryza. In the present experiments, we examined two experimental lines of turkeys with different genetic backgrounds. Poults from one line were selected from the other line based on 16-week body weight. Although infected poults of both lines developed clinical signs, we found that the larger, more rapid growing poults had significantly decreased average body weight when infected with B. avium compared to non-infected poults of the same line. Thus, we have shown for the first time that the genetic background of the poult influences the response to coryza.

Technical Abstract:
One hundred ninety-six male and female turkeys representing two genetic lines were experimentally infected with Bordetella avium. The lines of turkeys included a randombred control line (RBC2) and a subline (F) of RBC2 selected for increased 16-week body weight. There was no difference between lines RBC2 and F in the number of days to onset of clinical signs, and no mortality due to B. avium infection was observed in either line. Interestingly, however, there was a significant depression (12%) in body weight of F line poults infected with B. avium but no significant depression in body weight of RBC2 poults.